Field of the Invention
The invention refers to a device and a method for identifying refrigerants.
Description of Related Art
Because of legal requirements, various refrigerants are banned from use. In the automobile industry, for instance, the refrigerant HFO-1234yf will be used in the future instead of the previous refrigerant R134a. When an air condition system will be repaired in the future, it has to be possible to detect, for example, contaminations of the refrigerant HFO-1234yf by other refrigerants, such as e.g. R134a, in motor vehicle air condition systems.
For the purpose of detecting refrigerants, their different infrared absorption is used. In this regard, a gas cell is filled with the refrigerant to be tested (test refrigerant) and is radiated with infrared radiation passing therethrough. A sensor on the opposite side receives the radiation, with different parts of radiation being absorbed to a higher degree than others, depending on the refrigerants present in the gas cell. The absorption spectrum measured is converted into measurable electric voltage by the infrared sensor.
With the known measuring methods using infrared absorption, changes in temperature or in atmospheric pressure, ageing or a contamination of the gas cell cause measuring inaccuracies. A long-term stability of the measuring results can be achieved only with considerable effort.